Lock nut



Sept. 14 1926. l,599,995

J. G. ELMr-:R ET AL v Locx NUT Filed April 21. 1924 Patented sept. 14, 1926.

UhtiTEl) STATES .PATENT QFFICE.

JOHAN GUSTAF ELMR, OF ESKILSTUNA, HARALD FERNSTRM, OF SKOGSTORP, AND

CARL GUSTAF I-IK, OF ESKILSTUNA, SWEDEN.

'LOCK NUT.

Application filed April 21,4)1924, Serial No. '?0'7,984, and in Sweden April 26, 1928.

This invention relates to an improved look nut of the kind consisting of a wire of stcel or other resilient material wound into a cylindrical spiral corresponding to the threads of the Screw.

If a cylindrical Spiral with cross-cut ends is used as a look nut above a usual nut it will be found that it has a very small locking power even if it closely fits to the threads of the Screw-bolt in as much as the main nut on loosening exerts a stress on the lower en d of the Spiral spring in such direction that it tcnds lto expand the Spiral whereby the locking power by which the Spiral spring is secnred to the threads is essentially reduced.

It has also beenV proposed to provide an extension at the upper end of the Spiral which is bent downwards and brought into engagement with a boring'in the main nut to be looked. If the main nut shows a tendency to get loose the nut effects by said extension a tightening of the upper wind ings of the Spiral so that the locking power of'the .Spiral is increased. A lock nut of said construction is however difficult to use in as much as the main nut must be provided with a boring and the position of Said boring must correspond to the position of the downwardly bent upper end of the Spiral when the look nut has been screwed on and, furthermore, the rather great length of the downwardly bent extension causes that only a rather small tightening stress can be transmitted to the upper end of the Spiral.

The object of this invent-ion is to provide a lock'nut consisting of a cylindrical Spiral spring which can effect a very reliable locking without that any Special arrangements at the main nut are needed and without that it will be necessary to bring the ends of the Spiral into any distinct position in relation to the nut. 4

VVith this and otherobjects in view the invention consists, chiefly, in providing` an extension at one or both ends of the Spiral which extension is bent in such manner that it bears against the lirst winding at the opposite end of the Spiral. The lock nut is screwed onto the bolt above the main nut to be looked in such manner that the said' bent extension is jammed between the lowermost wmding of Spiral andthe upper side of the main nut.

'If the main nut shows a tendency to get loose on account of shakes and the like, the nut by friction on the said bent end of the Spiral, so that the upper windings of the Spiral are tightened the more Strongly the greater is the tendency of the nut to get loose.

In some cases we prefer to enclose the cylindrical Spiral spring into a sleeve having a bottom flange adapted to bear against the main nut to be looked as will be more specifically dcscribed herebelow.

In the accompanying drawing we have shown several embodiments of our invenspiral. 3 shows Screw bolt having` a look nut consisting of a cylindrical Spiral spring in direct contact with the main nut. Fig. 2 is a corresponding top view of the Spiral. Fig. 3 shows Screw bolt having a lock nut consisting of a cylindrical Spiral spring enclosed by a sleeve which engages the main nut. ing top view of the Spiral with the sleeve in section. Fig. 5 Shows av side view and Fig. 6 a top view of a modilication of the lock nut. i p

Referring now to Fig. 1 and 2, 5 is a Screw bolt with a main nut 2 and a lock'nut 3, the latter consisting` of a cylindrical Spiral .spring closely fitting to the threads of the bolt. The upper end of said, Spiral has an extension 1 which is bent downwards so that it lies below the lower end 4 of the Spiral which latter for that purpose is bent somewhat upwards as shown in Fig. 1. WVhen the look nut is screwed up .on the bolt the end of the extension l bears4 thus against the upper side of the nut 2. If the main nut 2 Shows a tendency to get loose it carries with it by friction the extension l of the Spiral so that the upper windings of the Spiral are drawn in to a tighter engagement with the threads of the bolt whereby the locking ofthe nut is Secured.` Experience has shown that this locking is effective up to the limit for the strength of the material and thata rather thin hardened Steel wire is suflicient for such locking up to the limit for the strength of the bolt and the main nut. n

In the embodiment shown in Figs. 3 and 4 the Spiral Spring 3 is enclosed by a sleeve 6 which bears against Vthe upper side of the main nut 2, the extension 1 of the tipper end of the Spiral being bent in such man- Fig. t shows a correspond-v ner that it bears against the bottom flange 7 of the sleeve. The sleeve 6 has an opening S for leaving room for the bent ends `l and 4:. If the main nut 2 shows a `tendency to get loose on the bolt 5 it Vearries with it the sleeve 6 by friction and the latter actuates then the extension 1 partly by the frietion between the flange 7 and the end of the cxtension l and partly by that the -rear edge 9 of the Opening 8 presses directly against the extension l so that the upper Windings of the spiral are drawn ltighter into the threads ofthe bolt the .greater is the tendency of the 'nut vto Vget loose.

In the modifieation shown in Figs. 5 and 6 both ends of the spiral have identieal extensions 1a and 1h Which are twisted together or loosely interlocked and bent in such manner that each of'them bears With its end on the opposite end Winding of'fthe spiral as clearly shown'in Fig. 5. By this symmetrical arrangementet the extensions of the spiral ends the locking effect Vainied at is reached independently of whether the one or other end of the spiral is turned towards the main nut, thus avoiding the possibility that the look-nut is accidentally applied in an ineffeetive inanner.

It -Will thus be seen that while 'the eX- tensions are iloosely interlocked so that either can be moved peripherally Vwith respect to the other fsufliciently to permit a tightening of the spiral, that extension Which is in frictionalengagement withthe nut'may be moved slightly =by th'einut in loosening.

At the same time the -extension lying agafnst the nut is movedfiin the'axial direction so that'its end Which is bevelled-and lies under the spiral turn that -is radjacent'the nut, is crowded against the side o'f thethread for additional frictional retardation.

This axial movementof the extension is alsoitransmit-ted to the extensionwvith which it interlocks, and its end, likewise, is crowded into frictional engagement with the thread of the bolt.

It will be noted that thefends of -theiextension aretbevelled and llieflunder the outer turns of thespringwvireand sufiiciently Close to them to prevent-these bevelled-ends 'from being forced outthe'groovein lt-he bolt land caused to jump over the threads. At theV same time these extensions-:are notso close to the endturns of-thefspiralas-toprevefnt the extensions from moving by the frietional engagement `with the nut.

lVe claim- 1. A locknut eomprising a spiral ofresilient material having turns adapted to fit to the grooves of a `thread and anouter end Crossing the spiral turns outsidethe spiral and bent to frictionally engagel any portion of the end face of thenutto tighten the spiral When the nut loosens.

2. A look nut comprising a spiral of resilien't material having an extension of its outer turn Crossing the spiral and bent to frictionally engage any portion of the end face of the nut, and the end of such extension bent to lie in the thread of the bolt carrying the first turn of such spiral to tighten the spiral When the nut loosens.

3. A lock nut colnprising a spiral of resilient material having an extension of its inner and outer turns both crossing the spiral and bent-to lfrictionally engage the end face of a nut, either of which extensions may engage such end face.

fl. A look nut comprising a spiral of resilient material having `an extcnsion on its ends crossing'the spiral and bent to frictionally engage the end face of a nut and the ends of such extensions bent .to engage the thread in Which the extreme turns of the spirals lie.

5. A lock nut comprising a spiral of spring Wire having turns adapted to 'fi't to the grooves of the thread and extensions of its ends orossing the spiral turns outside the spiral and loosely 'interloekech said extensions bent to frictionally :engage the end face of a nut.

6. A lock nut comprising a spiral of spring Wire having extensions on its ends crossing the spiral and bent to frictionally engage a nut, said'extensions loosely interlocked and having their ends extending in the grooves of the thread in Which the end turns of the spiral lie.

7. A lock nut comprsing Va spiral of spring `wire having extensions on its ends crossing the spiral and bent to loosely interloclgtlie ends of such extensions bevellet and lying under 'the outer turns of the spiral.

8. A look nut comprising a sleeve having an Opening in its side and a flange at one end, in combination With a resilient spiral in said sleeve, having :an `extension on its outer end passing through said Opening, Wherebywvhen flange and sleeve are lmoved bythe loosening ofthe nut, theledgeoffl-said Opening Will engage said extensionto tighten the spiral.

9. A lock nut eomprising a sleeve having a 'longitudinal slot and a flange at oneflend, in combination With a spiral (if-spring Wire in said sleeve, having extensions onitsends crossed and passingthrough-said-s'lot, Whereby When sleeve and flange farevfrictionally moved by the vloosening of thenut an edge of said extension Will engage the'extension on the outer endof the spiral-and tiglrten it.

In testimony Whereof We rhave-signed our names.

JOHAN GUSTAF AVELMR.

IUU 

